GaAs wafer and method of producing GaAs ingot

Abstract

Provided is a GaAs wafer that can suitably be used to produce LiDAR sensors in particular and a method of producing a GaAs ingot that can be used to obtain such a GaAs wafer. The GaAs wafer has a silicon concentration of 5.0×10 17 cm −3 or more and less than 3.5×10 18 cm −3 , an indium concentration of 3.0×10 17 cm −3 or more and less than 3.0×10 19 cm −3 , and a boron concentration of 1.0×10 18 cm −3 or more. The average dislocation density of the GaAs wafer is 1500/cm 2 or less.

The invention claimed is: 
     
         1 . An n-type GaAs wafer comprising:
 silicon with a silicon concentration of 5.0×10 17  cm −3  or more and less than 3.5×10 18  cm −3 ;   indium with an indium concentration of 3.0×10 17  cm −3  or more and less than 3.0×10 19  cm −3 ;   boron with a boron concentration of 1.0×10 18  cm −3  or more; and   zinc with a zinc concentration of 3×10 16  cm −3  or less,   wherein an average dislocation density of the n-type GaAs wafer is 1500/cm 2  or less.   
     
     
         2 . The n-type GaAs wafer according to  claim 1 ,
 wherein a carrier concentration is 6.0×10 17  cm −3  or more.   
     
     
         3 . The n-type GaAs wafer according to  claim 1 ,
 wherein the indium concentration is 1.0×10 18  cm −3  or more and 1.2×10 19  cm −3  or less, and   the average dislocation density is 500/cm 2  or less.   
     
     
         4 . The n-type GaAs wafer according to  claim 1 ,
 wherein a carrier concentration is in a range of 8.0×10 17  cm −3  or more and 1.4×10 18  cm −3  or less, and an absorption coefficient at a wavelength of 940 nm is 4.8 cm −1  or more and 7.2 cm −1  or less.   
     
     
         5 . The n-type GaAs wafer according to  claim 1 ,
 wherein a carrier concentration is 7.0×10 17  cm −3  or more and 8.0×10 17  cm −3  or less, and an absorption coefficient at a wavelength of 940 nm is 4.8 cm −1  or more and 6.8 cm −1  or less.   
     
     
         6 . A method of producing an n-type GaAs ingot, the method comprising performing a vertical gradient freeze method or a vertical Bridgman method using silicon as a dopant and using boron oxide as a sealant,
 wherein indium is used together with the silicon as the dopant, and zinc is not used as the dopant,   an amount of silicon charged is 70 wt ppm or more and 130 wt ppm or less with respect to a GaAs feedstock, and an amount of indium charged is 100 wt ppm or more and 5000 wt ppm or less with respect to the GaAs feedstock, and   an average dislocation density of the n-type GaAs ingot is 1500/cm 2  or less.   
     
     
         7 . The method of producing an n-type GaAs ingot, according to  claim 6 ,
 wherein the n-type GaAs ingot includes a part having a carrier concentration of 6.0×10 17  cm −3  or more.   
     
     
         8 . The method of producing an n-type GaAs ingot, according to  claim 6 ,
 wherein the average dislocation density is 500/cm 2  or less.   
     
     
         9 . The method of producing an n-type GaAs ingot, according to  claim 6 ,
 wherein the n-type GaAs ingot includes a part having a carrier concentration of 8.0×10 17  cm −3  or more and 1.4×10 18  cm −3  or less, and an absorption coefficient of 4.8 cm −1  or more and 7.2 cm −1  or less at a wavelength of 940 nm.   
     
     
         10 . The method of producing an n-type GaAs ingot, according to  claim 6 ,
 wherein the n-type GaAs ingot has a part having a carrier concentration of 7.0×10 17  cm −3  or more and 8.0×10 17  cm −3  or less, and an absorption coefficient of 4.8 cm −1  or more and 6.8 cm −1  or less at a wavelength of 940 nm.